Concentrated surfactant compositions and methods of preparation thereof

1. An aqueous composition comprising:

(a) an acyl isethionate of formula (I):

R 1 CO 2 CH 2 CH 2 SO 3 − M +   (I)

wherein R 1 is an alkyl or alkenyl group having from 7 to 21 carbon atoms and M + is a cation; and

(b) a further surfactant selected from nonionic surfactants, cationic surfactants and anionic surfactants other than those of formula (I);

wherein when component (b) is a nonionic surfactant it is selected from reaction products of aliphatic alcohols, acids amides or alkyl phenols with alkylene oxides;

wherein when component (b) is a cationic surfactant it is selected from quaternary ammonium compounds, polymeric cationic surfactants and dialkylaminoalkyl alkyl amides and salts thereof;

wherein when component (b) is an anionic surfactant it is selected from salts of C 12 to C 18 carboxylic acids, ethoxylated carboxylic acids, ester carboxylates and ethoxylated ester carboxylates and sarcosinates, alcohol sulfates, alcohol ether sulfates, alkyl sulfonates, alpha-olefin sulfonates, alkyl ether sulfates, alkyl sulfates, alkenyl sulfates, alkyl glyceryl ether sulfates, sulfosuccinates, sulfosuccinamates, sarcosinates, sulphoacetates, phosphate esters, acyl lactates, alkyl ether carboxylates, glyceryl ether carboxylates and isethionate compounds not of formula (I); alkyl aryl sulfonates; primary alkane disulfonates; alkene sulfonates; sulfonates of alkylphenolpolyglycol ethers; salts of alkyl sulfopolycarboxylic acid esters; alkyl sulfosuccinates and salts thereof, alkyl ether sulfosuccinates and salts thereof, sulfated derivatives of fatty acids and polyglycols; alkyl and acyl sarcosinates; sulfoacetates; alkyl phosphates; acyl lactates; salts of lipoamino acids;

wherein component (a) comprises at least 11 wt % and up to 40 wt % of the composition;

wherein component (b) comprises up to 30 wt % of the composition;

wherein component (a) and component (b) together comprise more than 18 wt % and up to 60 wt % of the composition;

wherein the composition is substantially free of taurate surfactants or comprises less than 2 wt % of taurate surfactants;

wherein the composition is substantially free of alkanolamides or comprises less than 0.1 wt % of alkanolamides;

wherein the composition is substantially free of alkylamine oxides or comprises less than 0.1 wt % of alkylamine oxides; and

wherein the composition is a flowable composition at one or more temperatures between 15° C. and 45° C.

2. The composition according to claim 1 which comprises at least 12 wt % and up to 25 wt % component (a).

3. The composition according to claim 1 wherein component (a) comprises one or more of sodium lauroyl isethionate, sodium cocoyl isethionate or sodium oleoyl isethionate.

4. The composition according to claim 1 wherein component (b) comprises said anionic surfactant.

5. The composition according to claim 4 wherein component (b) is selected from the group consisting of alkyl sulfates, alkyl ether sulfates, sarcosinates and isethionate compounds not of formula (I).

6. The composition according to claim 5 wherein component (b) comprises an alkyl ether sulfate of formula (II):

R 1 (OR 2 ) n OSO 3 − M +tm (II)

wherein R 1 is an alkyl group having from 7 to 22 carbon atoms, R 2 is an alkylene group having 1 to 4 carbon atoms, n is from 1 to 12 and M + is an alkali metal or optionally substituted ammonium cation.

7. The composition according to claim 1 wherein component (b) is selected from the group consisting of alkyl sulfates, alkyl ether sulfates, sarcosinates, alkoxylated sugar esters and dialkylaminoalkyl alkyl amides.

8. The composition according to claim 1 which further comprises a component (c) comprising an amphoteric, betaine or sultaine surfactant.

9. The composition according to claim 8 wherein component (c) comprises a betaine.

10. The composition according to claim 9 wherein component (c) comprises cocoamido propyl betaine.

11. The composition according to claim 8 wherein component (a), component (b) and component (c) together comprise at least 20 wt % of the composition.

12. The composition according to claim 1 which is substantially free of taurate surfactants or comprises less than 0.1 wt % of taurate surfactants.

13. The composition according to claim 1 which comprises less than 1 wt % of compounds of formula (III):

in which one of R 2 and R 3 is hydrogen and the other is an alkyl group having from 1 to 4 carbon atoms and R 1 is an alkyl or alkenyl up having from 7 to 21 carbon atoms.

14. A formulated personal care composition prepared from a composition as claimed in claim 1 .

15. A method of preparing a personal care composition, the method comprising diluting the composition of claim 1 .

16. The composition according to claim 1 which is substantially free of imidazoline amphoteric surfactants or comprises or less than 0.1 wt % imidazoline amphoteric surfactants.